In the novel Five Little Pigs, Louise is the cousin of Amyas Crale. She lived in Canada with her husband. After the death of her father Amyas Crale, the young Carla Lemarchant was sent to Canada and brought up by her “Aunt Louise” and her “Uncle Simon”.
Louise does not appear in person, but Carla does mention her. She says that Uncle Simon and Aunt Louise were sweet to her, and that Aunt Louise had told her that Lemarchant was her name in Canada.