The ornamental design for a lamp handle, as shown and described.
FIG. 1 is a perspective view of a lamp handle according to the present invention;
FIG. 2 is first side view of the lamp handle of FIG. 1;
FIG. 3 is a front view of the lamp handle of FIG. 1;
FIG. 4 is a second side view of the lamp handle of FIG. 1; and,
FIG. 5 is a back view of the lamp handle of FIG. 1.
The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design while all other broken lines are directed to portions of the article which form no part of the claimed design.