21. For the purposes of section 55 of the Act, the following is contemplated:
(a) employment described in section 5, in the first paragraph of section 8 and in section 10, where the employer has not signed any agreement or arrangement, as the case may be;
(b) employment excepted by sections 13 and 20;
(c) employment excepted by paragraph a of section 3 of the Act,
where the employee who performs it resides in Québec within the meaning of section 8 of the Act, or is deemed to be employed in Québec in accordance with the Taxation Act (chapter I-3).