Born Mary Leta Dorothy Slaton in New Orleans on December 10, 1914, Dorothy's parents divorced soon after her birth. Her mother later remarried to a man named Lambour, the source of Dorothy's future stage name. Dorothy dropped out of school at age 15, forging her mother's name on school documents, and went to work to help support her family. She later attended secretarial school. At age 16, she was crowned Miss New Orleans, after which she and her mother moved to Chicago, where Dorothy worked as an elevator operator at Marshall Fields.
According to http://www.parabrisas.com/d_lamourd.html