300. A person holding office as a member of the council is disqualified from holding office as such(1) for the whole term of office if he was elected while ineligible;
(2) upon ceasing after 1 September of the calendar year in which the election was held, to meet the eligibility requirements prescribed in section 61, until he again meets those requirements;
(3) upon becoming ineligible under section 62 or 63 after his election, and as long as he remains ineligible;
(4) if he was a member of the Parliament of Québec or of Canada when he was elected to the council and did not cease to hold that office thirty-one days after taking his oath of office as a member of the council, as long as the plurality continues;
(5) if he begins to hold office as a Member of the Parliament of Québec or of Canada after his election, as long as the plurality continues.