Is it obligatory for a student to perform Friday Prayer in the prayer hall if its unspecified time conflicts with lectures, given that he prays Dhuhr immediately after leaving class?

The questioner must try to agree with those in charge of the mosque to set a suitable time for everyone that does not conflict with Friday prayer. If he is unable to do so, then it is not permissible for him to miss Friday prayer because of the lessons, and he must seek permission from his teacher. Friday prayer is an obligation upon every sane, adult, free, resident Muslim male who is not excused. If his attendance leads to harm to his property, person, or livelihood, then he is permitted to miss Friday prayer due to that harm; otherwise, attendance is obligatory.