A trim component or strip for a siding system is disclosed. In one embodiment, the component includes an elongated body having an outwardly bowed portion that simulates the appearance of a log or timber. The trim component also includes an integral receiver for receiving a portion of one or more siding strips, such as either a side edge of a single siding strip or an end of a plurality of siding strips, depending on the relative orientation of the component and the strip(s). A pair of trim components may also be provided for trimming adjacent sides of the wall opening, in which case at least one end of one of the components may be miter cut and overlap with the corresponding end of the adjacent trim component. Alternatively, the corresponding ends of at least one pair of adjacent trim components may be miter cut and fit in an abutting relationship to form a miter joint.