I don't think we have any debate over whether the Pharaoh was proud, arrogant, and sinful. In context of the thread -- re whether God controls any of men's thoughts and/or actions -- the question is whether God was active in hardening Pharaoh's heart, controlling the actions, reactions, and the outcome. God says he did.
Perhaps it is not too much of a quibble to note that Exodus 4:21, the first mention of hardening Pharaoh's hear, precedes Exodus 5.
Perhaps it is not too much of a quibble to note that Exodus 4:21, the first mention of hardening Pharaoh's hear, precedes Exodus 5.