The ornamental design for a solarlawnmower, as shown and described.
FIG. 1 is a front-top-left perspective view of a solar lawnmower showing my new design;
FIG. 2 is a rear-bottom-right perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left elevational view thereof;
FIG. 6 is a right elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines showing cleats in FIG. 1 through 8 are included for the purpose of showing environmental structure and form no part of the claimed design.