I don't mind Louisa but not especially keen on the 'Loo' sound and 'Lou' often ends up as a nn.
Other ideas:
Aurora, Alexandra, Aurelia, Arabella, Annabella, Beatrice, Bianca, Claudia, Cecilia, Carolina, Cassandra, Clarissa, Cordelia, Dorothea, Evangeline, Florence, Georgina, Georgia, Gabriella, Genevieve, Hannah, Helena, Joanna, Josephine, Katherine, Liliana, Lucinda, Mary, Maria, Miranda, Natalia, Natasha, Philippa, Rebecca, Ruth, Rosanna, Sarah, Saskia, Tabitha, Viola, Victoria