She lived in England for 6 years and became an English citizen there which would fast track her Canadian citizenship. She and her husband would never have be allowed to own a business in Canada if she were not a citizen.
Mr. Wilson said neither of them gave up their U.S. citizenship. Below is a link to Michael Wilson’s Report of an American Citizen document. Ted’s older half-brother died in December 1966; his mother moved to Louisiana in 1967. Why would she become a British subject for less than a year?
http://vidrebel.wordpress.com/2016/04/22/citizen-journalist-takes-on-ted-cruz/
The above link’s purpose is to prove he isn’t eligible. It is flawed, particularly trying to pass off an Oswald associate as Cruz’s father. If nothing else, at least the above documentation makes the chances of his mother renouncing her citizenship in Britain seem extremely unlikely.