It has a seperate arm but what usually ends up happening is the bit that attaches to the base of the chair turns instead and i then need to push the chair around at an angle to get away from the desk and chair

Another odd thing to get used to is the chair will turn but the stand wont

So if you want to line the stand and the chair up with the monitor you first have to line up the stand by moving the legs of the chair into position and then rotate the top of the chair to be in front of the stand and monitor