Star pianist Louis Lortie's big break

French-Canadian pianist Louis Lortie's big break came when he had a big break which meant he played with his leg in a cast.

It's 2003 and Robert J Harth is facing every arts administrator's nightmare: the star soloist has cancelled. Worse, it's Maurizio Pollini, arguably the world's greatest living interpreter of Chopin, who has promised to play half a programme of the composer's music to a jam-packed Carnegie Hall, where Harth is executive and artistic director. Any replacement will have to be at the very top of his or her game.

Louis Lortie, the French-Canadian pianist shoulder tapped to step in, is not at the top of his game. He has fractured his knee in a skiing accident. Moreover, Lortie has never played Carnegie Hall. Despite a flourishing 20-year career, he's barely played New York and not at all in the previous two years. When Lortie makes his way to the stage he is on crutches and must rest his right leg on a block for elevation. He launches into a programme of Chopin etudes and brings the house down.

"It's so long ago now," says Lortie, who this month performs Rachmaninov's Piano Concerto No.2 in Auckland, Wellington, Christchurch and Dunedin with the NZ Symphony Orchestra. "I've had other concerts [at Carnegie Hall] since and it's always an incredible thrill. The first thing you think about when you go to rehearse in the afternoon is the number of famous people who have walked on that stage; it's quite a thing on your shoulders."

Standing in for a legend like Pollini – that's another thing on the shoulders. "When you replace someone they are usually more famous than you," Lortie concedes. "And you have to contend with the audience, who have come for that musician and expect you to deliver as well if not better than the proposed artist." Here we are now, entertain us.

While Lortie is particularly admired for his Chopin, Rachmaninov is part of his family DNA. Lortie's grandmother saw Rachmaninov perform live and was at the premiere of the composer's Variations on a Theme of Corelli.

"Rachmaninov was always a figure that intrigued me because I heard from my grandmother about the way he played and wrote music; we talked about that a lot."

The second piano concerto is the most famous of Rachmaninov's orchestral works but Lortie has only recently returned to it after several years away.

"It's nice to go back," he says. "It's a very improvisatory piece and there are so many ways to play it and so many things you can change according to your mood or the acoustics or the piano."

Does music stay under Lortie's fingers or must he relearn a neglected score?

"Sometimes you open a score after a few years and you think, 'Oh my God, it will never come back,' and then after a few hours or a couple of days it comes back suddenly. It's like a drawer that's been locked and you suddenly find the key."

He will pray to the patron saint of locksmiths next year when he plays all 32 Beethoven piano sonatas to celebrate the composer's 250th anniversary. It's the first time Lortie has tackled the complete set for 20 years and he admits there are several he's not performed since. He expects his new interpretations will bear little resemblance to those from two decades ago.

"That's the main reason I wanted to do it again; my vision has changed so much. After all this time some of them will be unrecognisable. In some cases even the choices of tempi will be completely different because I have another vision of the music."

These days Lortie pays particular attention to dynamics and contrasts and says modern pianos mean that people tend to play too loud.

"All the instruments are so bright and flashy, which is different to what was intended [when the composers wrote the music]. We have to adjust to the times and the different halls but I think maybe we exaggerate dynamics. You rarely hear people talking about softer sounds, and that's disappointing to me. When I see a conductor ask for subtlety and fine nuances I'm always very happy."

Lowdown
What: NZSO - Transfiguration, featuring Louis Lortie.
Where and When: Wellington, Auckland, Dunedin and Christchurch, Friday, September 6 to Saturday, September 14.