We know Lorde will be in NY on March 11th to appear on Saturday Night Live.
There's an ad featuring the "Royals" singer being aired since this Monday morning on New Zealand television. March 2 in NY and March 3 in New Zealand occur at roughly the same time, so the ad may be indicating a simultaneous release.
The cryptic ad ends with the dates "3.2.17 NYC" and "3.3.17 NZ", indicating that a new song might be ready to drop on Friday.
Since we only have breadcrumbs to work with at this point, here's something: Lorde also changed her Twitter bio recently.
In November (16) she updated fans of her progress, tweeting a picture of her listening to new tracks in the studio.
Lorde released her debut album Pure Heroine in the United Kingdom in November 2013, where it reached Number 4 on the Official Albums Chart. She's slated to make her solo debut on Saturday Night Live on March 11th, plus she's got festival sets already marked down for Coachella and the New Orleans Jazz and Heritage Festival, which both go down in the next couple of weeks.
Lorde previewed what is thought to be the first single from her sophomore album last night (February 26).