DANCING DAYS: It’s back to the source — in more ways than one — for Christian Lacroix. The National Costume Museum in Moulins, France, which hosted a 2007 retrospective of Lacroix’s costume designs, will now put the spotlight on a standout 2011 production. The focus of “Christian Lacroix, La Source et le Ballet de L’Opéra de Paris” (or “Christian Lacroix, La Source and the Ballet of the Opera of Paris,” in English) will be the Swarovski Element-embroidered costumes he designed for the latest production of “La Source,” a 19th-century ballet with a cast of harem girls, Cossacks and nymphs. The exhibit is to run from June 16 until Dec. 31 and offer a scene-by-scene look at the accessories and costumes.