Toronto District School Board says virtual school for elementary students will begin two days later, on Sept. 17.In a memo posted on the TDSB website Thursday, the board said it needs more time due to the large number of families — more than 66,000 students — that selected the online learning option.“We require additional time to staff and timetable to ensure a more consistent opening for all staff and students,” TDSB said.“Our top priority is to ensure students experience success in both our in-person schools and virtual schools.