The couple in Indiana in 1921...
U.S. City Directories, 1821-1989 (Beta) about Armand LagneauName:
Armand LagneauGender: M (Male)
Residence Year: 1921
Street Address: 1021 S Ohio
Residence Place: Kokomo, Indiana
Occupation: Shop Cleaner
Spouse:
Giovannia Lagneau Publication Title: Kokomo, Indiana, City Directory, 1921
In the 1938 City Directory Joan is listed as
widow of Armand...
click once to enlarge and again to magnify

Took a look at the manifest...Joanie Lagneau (wife of Armand) has a place of birth listed as "Solbirona, Italy" (don't know this name)
She is leaving HER brother "Deseret Deanchamp" in Paris ?
Going to Kokomo to Armand's son Vincente La Biancha ?
Where does the TOSSI surname come in?
EDITED to add:
Located an additional ship manifest for Joan Tosi Lagneau in 1929.Sailing from Buenos Aires, Argentina on Sept 5, and arriving NY Sept 24 on SS American Legion
Her last permanent residence is listed as Kokomo, Indiana, but her travel visa issued in Buenos Aires.
Her place of birth is listed as SARTIRANO, Italy.
Possbilities...Sartirana Briantea, comune of Merate - province: Lecco - region: Lombardy
Sartirana Lomellina, comune of Sartirana Lomellina - province: Pavia - region: Lombardy
Sartorona, comune of Pieve Porto Morone - province: Pavia - region: Lombardy
Sarturano, comune of Agazzano - province: Piacenza - region: Emilia Romagna
She is listed as married, so Armand may not have died until after 1929.
She is on line 2...

T.