I found this online on CIC website:Raheel27a said:Yeah thats what i researched too but i told my wife to bring employment letter with you because if CHC require any proof about returning back to canada then we will be able to present that emplyment letter to them
"Permanent residents residing abroad may not sponsor from outside of Canada. Canadian citizens travelling as tourists are not considered to be residing abroad"
"In order to sponsor, you must live in Canada or provide evidence , if you are a Canadian citizen living outside of Canada, that you will live exclusively in Canada once the person you are sponsoring becomes a permanent resident"
I would just classify myself travelling as a tourist, I am therefore not residing abroad. But yes, the second part shows that it would be helpful to have a letter from sponsor or a house in her name so you can provide proof that you guys both want to settle in Canada.