Using JR pass before student visa starts

Hello,

I will be studying in Japan for a semester starting mid September. I would like to visit Japan two weeks before my classes start.

If my student visa were to start September 7th, can I enter the country two weeks prior (let's say August 24) as a tourist and therefore be eligible for a Jr pass ? Would I have to exit the country and re-enter it before my student visa start date? Or can I simply be considered a "temporary visitor" until my student visa starts (and therefore be a eligible for a Jr Pass during that 2 week period prior to my student visa start date) and stay in the country until the end date of my student visa?

Thank you for you help

Best regards,

Johann