You didn't say whether you had Blanche's birth certificate.
Just in case, here it is:
https://www.archivesdepartementales76.net/ark:/50278/8da78501426520634def4689f5ad889e/dao/0/165 Entry 888
Let me know whether you need help translating it.
I don't think I translated Blanche's birth certificate for you. So here's a translation for you:
On the thirteenth of May, eighteen hundred and eighty-five, at two o’clock in the afternoon, a birth certificate was drawn up for
Blanche Jeanne Kitson, female, presented to us and born on the eleventh of this month at ten-thirty in the evening, at the residence of her parents, 5 Rue Desmaret.
She is the daughter of Benjamin
Kitson, aged twenty-eight, a Carding Machine Setter, and Anne
Shaw, also aged twenty-eight, housewife, married in Manchester, Parish of Saint Oswald (England), on the twenty-fourth of August last.
This declaration was made before us, Deputy to the Mayor of Rouen and delegated Registrar of Births, Deaths and Marriages, by the child’s father, in the presence of Messrs. Louis Paul Deglatigny, aged thirty, an industrialist residing at 21 Rue Jeanne d’Arc, and Gustave Pierre Simon, aged thirty-eight, a commercial traveller residing at 8 Place du Vieux Marché.
After the reading of this document, it was drawn up in duplicate and signed by all parties present.