They're set out on pages 6 and 7 of the test from that manual. These apply, for example, to a person who is travelling on business, but their family lives in Canada and their children go to school here and they have a house or a residence here. It depends on whether they've centralized their mode of existence—that's the language from the case law—in Canada. It depends also on the extent of the absence from Canada. If you've got a large gap, it may be harder to justify.
The last factor that's listed—and this is again from the citizenship processing manual prior to Bill C-24—is what is the quality of their connection with Canada? Is it more substantial than that with another country? For example, if your constituent is more established in the Gulf, then it would be harder for him to be accepted as a Canadian citizen.