No. It is fine either way. In this sentence, "like" is a transitive verb. In "I like when it is easy," "when it is easy" is the direct object. In your suggestion, "when it is easy" is what we call an object complement renaming "it," the direct object.
I also had "lorsqu'il". Why is this wrong? Another query: can "lorsque" not be used at the end of a sentence? For "and when?", the given answer was "Et quand?".