The ornamental design for a bellornament, as shown and described.
FIG. 1 is a perspective view of a bell hanging decoration showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is bottom plan view thereof.
The broken line showing of a ribbon, star and circuular shaped openings is included for the purpose of illustrating only and forms no part of the claimed design.