Using the Hardy Weinberg model, any change in allele frequencies is evolutionary but this includes phenomena such as genetic drift and founder effects which do not necessarily lead to changes which make individuals better adapted to survive and reproduce. Natural selection is the only driving force for evolution which, by its very nature, always picks the best adapted individuals to survive and contribute to the next generation, leading to better adapted individuals in the next generation.
Work Step by Step
Consider all the things which can drive evolution and how often each may lead to better adapted individuals. The only "always" should be for natural selection, by definition the driving force for evolution outside human endeavors like agriculture in which artificial selection is the driving force.