She later tweeted that what she had said was "really insensitive" adding she was "sorry".
However, the damage appeared to be done, with Swift leaving out any of Lorde's songs from a Spotify playlist of her favourite tracks.
But last week the pair were apparently together again, with American media reporting Swift, Lorde and female American rock trio Haim were spotted exiting a plane in New York.
The group hid themselves from waiting paparazzi by covering their heads with umbrellas.
Fans shared the pap photos on Wednesday, with some suggesting Lorde was in the US to prepare to start promoting her upcoming third studio album.
Last month she wrote on social media that album number three as "in the oven".