The designer: He’s known for his lace and sweet sophistication. Once the one-to-watch, Chinese-born London-based Zhang now commands our full attention—and with good reason.   This season it’s about: His elevated couture sensibility (earned at the likes of Dior) finds its way onto decorative denim and daywear via 3D embroidery, sequins and cloud lace.   The piece to buy: The irresistibly pretty white sequin ruffle dress.