PARIS — “My inspiration this time is David versus Goliath; it’s romanticism with a touch of audacity, like embroidery over a leather skirt,” says Christian Lacroix of the spring collection he’ll show Sunday. Valentino, who’s thinking less metaphorically, says the collection he’ll present Wednesday will be “characterized by different layers of lightweight fabrics that are sewn together.” Here, a last-minute look at what they’ll show.