The ornamental design for a sprinklerhead for a lawnsprinkler, as shown and described.
FIG. 1 is a top perspective view of a sprinkler head for a lawn sprinkler
showing my new design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a top plan view thereof; and
FIG. 4 is a side elevational view thereof, the sides opposite and adjacent
being identical in appearance, with the broken-line showing of the
sprinkler base being for illustrative purposes only and forming no part of
the claimed design.