NEW YORK — Christian Lacroix is a master of fantasy, and so it stands to reason that he’s often at his best for evening, which brings out the eccentric splendor for which he’s known. And his spring couture collection didn’t disappoint. There were evening stunners ranging from an organdy and organza dress with red bows to a floral and striped coat over an Empire gown with fuchsia flowers. Lacroix was one of a number of designers this season who showed striking numbers with back details. Here, his ruched gown with a deep back V underscored by a ribbon and rosette. For more on the season, see photospread Baby’s Got Back.