Newly single Karen Elson played a set from her album, “The Ghost Who Walks,” Monday night at the jam-packed Junior Spring Benefit for the Lincoln Center Institute. But asking her about last Friday’s highly publicized party to celebrate her sixth anniversary and divorce from White Stripes rocker Jack White didn’t go over as well. “Oh, I don’t want to talk about that,” Elson growled. Carey Mulligan, Mamie Gummer, Zoe Kazan and Lily Rabe chaired the event on the Gramercy Terrace, where partygoers included Hayley Bloomingdale, Grace Gummer, Paul Dano and Charles Rockefeller. Guests buzzed when Adam Dell arrived with a “mystery brunette,” whom more than one called a “look-alike” of his ex, Padma Lakshmi. Downstairs, a group of smokers — and a Page Six reporter — were surprised when a planter knocked from the roof came crashing down 16 floors to the sidewalk. We presume Elson wasn’t exacting her revenge for our unwelcome question.