Just for you I went out to take a look and confirm. Under/inside the wiper arm there is a large spring which holds the blade to the window. If it gets some ice in between the coils of the spring, as it might when you lifted the arm and stretched the spring, it could prevent it from pressing the blade to the glass. Pull the blade to the upright position and feel under the arm for ice in the spring coils. Lifting it up and down a few times "might" loosen any ice.