Work backwards from the first day services must be delivered, allowing for the state practice requirements and the background checks that school work involves. Admission is granted for a period not exceeding three years and is tied to the employment described, so applying before the structure is settled produces an authorization that does not match the work.
The academic calendar is not the binding constraint
Hypothetical example: Imelda is a Callander social worker offered an American post for the coming academic year. An academic year looks like a firm deadline, and it pushes people to apply as soon as an offer exists. The steps that actually take time sit elsewhere.
State practice requirements can involve an application, supporting documentation and a waiting period. Background and vulnerable sector checks for school-based work are slow and cannot be accelerated by an employer's urgency. The contractual question of who employs Imelda may itself need renegotiation between the organization and the districts.
Only once those are resolved does the letter describe something real. Two improvisations should be avoided in the interval: beginning intake or consultation work remotely for the American organization from Ontario, which raises the question of when the employment started, and travelling as a visitor to attend orientation and then doing productive work. If the year cannot be met honestly, the conversation belongs with the employer.
Holding the post for a term is a conversation employers have more often than applicants expect.