A square will always be a parallelogram due to the definition of a square.
A parallelogram is a quadrilateral with two pairs of parallel lines. Each two opposite sides are equal and none of the angles is right.
A square is a quadrilateral with 2 pairs of parallel sides, all right angles and all congruent sides.
Since it is part of the definition, it is impossible to have a square that is not a parallelogram.