A teacher shall retain but not accrue seniority if the teacher is:
on leave of absence in excess of 30 calendar days, except as set out in Article .11(d) hereof
laid off for a period of time less than that set out in Article .10(d) hereof
absent because of illness or accident for more than one year provided however that the first year of illness shall be counted as service for seniority purposes
absent because the Institute has granted more leave than required by those leaves specified in Sections 34.1, 34.2 and 34.3 of the Employment Standards Code, provided however that the amount of time specified as leave under the provisions of the Employment Standards Act shall be counted as service for seniority purposes.