windshueld wiper arm adjust renault fluence 2010

I have to adjust the direction of the windshield wiper arm on the driver's side of my renault fluence 2010. They told me to unscrew the screw on the bottom of the arm, lift it and place it 2 cm higher. I unscrewed the screw but it is impossible to lift the arm. Is there a special technique to get the wiper arm from its place?