Joceline Sanschagrin is the author of Caillou and Gilbert , Caillou: Baby Sister , Caillou Helps Mommy , and Caillou: Potty Time . Eric Sevigny is a graphic artist and the illustrator of numerous Caillou titles, including Caillou: ABC Train , Caillou: Every Drop Counts , Caillou: Happy Holidays, and Caillou: The Magic of Compost . They both live in Montreal, Quebec.