I think Elizabeth didn't die until she was an old woman! Her sons being with other relatives in the Census doesn't mean they lived at that address all the time (or if they did, that mother had given them up or abandonded them) as the Census is just a snapshot of a dwelling's human configuration on one night!
1861: Narborough Hall, Narborough, Leicestershire
RG 9/ Piece 2257/ Folio 77/ Page 10
The home of William ORTON, a Surgeon. Among his servants:
Servant: Elizabeth POLE 49, Mar, Cook, Dom Serv, b Huncote
1871: Narborough Hall, Narborough, Leicestershire
RG10/ Piece 3233 / Folio 78 / Pg11
The home of William ORTON, a Surgeon. Among his servants:
Servant: Elizabeth POLE 60, Mar, Cook Domestic Servant, b Huncote
Servant: Martha SEWELL 19, Housemaid Domestic Servant, b Huncote
1891: Narborough, Leicestershire
RG12 / Piece 2500 / Folio 63 / Pg19
Head: Elizabeth POLE 80, widow, living on own means, b Huncote
Next door:
Head: William SEWELL 83, wid, b Huncote
Wife: Mary SEWELL 81, b Narborough
DEATH: FreeBMD
Jan Qtr 1896, Blaby: Elizabeth POLE age 85
PROBATE:
Elizabeth POLE of Narborough, Leicestershire, widow, died 29th Dec 1895.
Probate Leicester 7th January 1896 to Richard POLE Storekeeper and Frederick POLE Shoemaker. Effects £63 13s.
A couple of Census gaps - looking for them now

Cheers
AMBLY