FIG. 1 shows a perspective view of an illumination lamp having the ornamental design of the present invention;
FIG. 2 shows a front plan view of the illumination lamp of FIG. 1;
FIG. 3 shows a back plan view of the illumination lamp of FIG. 1;
FIG. 4 shows a left side plan view of the illumination lamp of FIG. 1;
FIG. 5 shows a right side plan view of the illumination lamp of FIG. 1;
FIG. 6 shows a top plan view of the illumination lamp of FIG. 1; and,
FIG. 7 shows a bottom plan view of the illumination lamp of FIG. 1.