Lou, Louie, Lulu.
Famous people named Louisa:
Novelist Louisa May Alcott; actress Louisa Krause; singer Louisa Johnson; former U.S. First Lady Louisa Johnson Adams.
In the play (and film) Steel Magnolias, the caring-but-cantankerous Ouiser's real name was Louisa.
180+ Sweet Old Lady Names Rooted In Tradition, If You Like Sophia, You’ll Love …, Lovely L Names For Baby Girls, Beyond Bella and Abby: Girl Names With Natural Nicknames, I Declare! Girl Names With Country Charm,