Magnetic momentum alignment and precession

[aleees]

In my lecture notes on paramagnetism and diamagnetism is stated that "according to van vleck critical considering an electron in motion around the nucleus diamagnetic and paramagnetic effect compensate (classical)"
The proof following takes the intrinsic momentum related to L as the momentum that in paramagnetism would "line up" due to the torque.
My question is, how can i have momentum alignment if there is larmor precession?

 

[Dr_Nate]

From what you wrote it is difficult to understand exactly what is going on, but it sounds like your notes are trying to give a hand waving classical argument to a quantum mechanical calculation.