Not sure if its him, but on the 1841 census there's a Josh France in Back Brook St [Chorlton Upon Medlicot subdistrict] aged 20, warehouseman, with a 12 yr old called William Thornhill
This could be the William Thornhill baptised Manchester 23 Jun 1830, s/o William & Hannah
Thornton Thornhill, a Cotton Spinner of Chorlton Row
On 19 May 1821 William
Thornton Thornhill, Cotton Spinner & Bachelor married Anna France, Spinster at Manchester. Both signed X.
The only other child I can find for them is Mary in 1832, who I think is the Mary aged 3
1/2 buried at Chorlton in February 1836.
I cannot find William or Hannah in 1841. There was another couple of the same name having children around the same time, although that William is a Stay Maker & married Hannah Stoby.
Could Joseph therefore be the illegitimate son of Anna/Hannah France?
ADDED: Possibly worth enquiring here:
http://www.rootschat.com/links/01jzd/