I'm not sure exactly how your lx and lz are being changed, but if you want to rotate a point, and know where it actually is, you should do so using a rotation matrix. You should have a point as what you are looking at, and then rotate it around your character - as far as i can tell, you are just rotating the world around using glRotatef. Another advantage to rotating a point is that you can then easily change the direction of your character to walk towards it, while glRotate will not necessarily allow you to do this.
Have a look here for an explanation of rotation matrix http://en.wikipedia.org/wiki/Rotation_matrix or just Google them.
Note: The thing that caught me the first few times with opengl is that when using the math lib for cos an sin - that it uses radian's .. not degrees ! Keep this in mind