You could well be right (about James and Ann), I'm sure there's more than one possibility. To be certain you need to get a copy of the 1872 marriage certificate which should show the name of Elizabeth's father. I saw the James/Ann listing in the 1851 census, and it could be either. I suppose I tend to stick to 'what is known, then go one step back' method.
If Elizabeth was married in Preston in 1872 I thought there was a good chance she would have been living there the year before, which means the 1871 census. Although there are differing births around the 1848/50 period, I can only see two of them living in Preston in 1871. The other is a lodger age 32, which is why I suggested the Patrick/Ann family.
BUT... I was wrong! Just double checked the lodger who is transcribed as 32, I think it's not 32 but 22 when you look at it, and guess what?
Elizabeth the lodger is living next door to a family called Holland - Catherine, Wilfred, Mary etc etc! That really would be too much of a coincidence, so the Irish Cloth Hawkers now seem to go out of the window...
Unfortunately because Elizabeth is lodging (with a Widow called Jane Emmet, and her sons Joseph and Charles) it doesn't show any family. All it gives is age 22, Cotton Weaver, born Preston. Need to find her in 1861..