With Rouen secured, you are too strong to reduce without a lengthy siege. There are still many Normans at large who support you over William of Talou. While you defy your enemies, the duchy is given over to scores of small-scale fights and and much pillaging of the open countryside. Henry's confidence wanes, and he decides to withdraw until he can gain reinforcements. You now have a choice to make:
Remain secure at Rouen and prepare for a lengthy siege.
Gather your immediate forces and besiege your uncle William at Arques.