23. For the purposes of this subdivision, “period of exemption” means the period beginning on the date on which the borrower obtains a first loan, or on which he becomes a full-time student again after having ceased to be so, and ending(1) on 1 April, for a borrower who completes or abandons his full-time studies during or at the end of the preceding summer trimester;
(2) on 1 August, for a borrower who completes or abandons his full-time studies during or at the end of the preceding autumn trimester;
(3) on 1 January, for a borrower who completes or abandons his full-time studies during or at the end of the preceding winter trimester.