Complex sentence: She discovers that the man is not Uncle Horst but is a man named Ari who takes Madeline to a lace factory to work for La Croque and discovers other young girls work for her as well.
Split into simpler sentences: She discovers that the man is not Uncle Horst but is a man named Ari. Ari takes Madeline to a lace factory to work for a woman named La Croque, and Madeline discovers other young girls work for her as well.