There is quite a genealogical prize for this one as she was the illegitimate daughter of James Disraeli, brother of the Victorian prime minister Benjamin Disraeli. She disappears after the 1891 census when living with her sister Annie, and half brother William at 171-172 Sloane Street, Kensington. There is no record of either a death or a marriage up to 1911, nor is there any indication that she emigrated, although this has to be a distinct possibility. I am undertaking this research both out of personal curiosity and as a volunteer of the National Trust, Hughenden Manor, Buckinghamshire, England, Benjamin Disraeli's old home.
If anybody has any idea what became of Louisa, I would be very grateful if you would let me know.