To Argentina.There is a passenger record of her on Ancestry.com. That is where I get the name Jeanne Tosi Lagneau.I believe she married a widower (my great grandfather) Armand Laino (1985 Argentine census list that spelling although should be spelled Lagneau) whose 1st wife Rosa (I assume) must have died??Jeanne, Armand and daughter must have returned to Choisy France in 1916 (date listed on Matilde's US Passport application) and everyone came over in 1920 to USA.Mathilde under Mathilde Lo Bianco married to Vincenzo.
I am just fishing.I can find no record of Tosi/Tossi in all the Ancestry.com/Italy census records.Quick looks, but still no exact matches.I do not know the exact dates she went to Buenos Aires, but her US obituary for Joan Mary Lagneau in 1945 lists 6 siblings in South America and 2 in Italy.
Her birth, her marriage to Armand would be the final key to complete the tree.