符存審
Energized by Lu's arrival, as Lu was able to serve as a guide for attacks on Jin territory, Khitan's Emperor Taizu decided to launch a major attack on Lulong. Later in the spring, the Khitan army, with Lu serving as its guide, attacked and quickly captured Xin Prefecture. When Li Cunxu ordered Zhou to counterattack with Lulong troops, joined by Zhao and Yiwu troops, they were defeated by Khitan troops, and Zhou was forced to flee back to You Prefecture. The Khitan forces subsequently put You Prefecture under siege, and Zhou requested emergency aid from Li Cunxu. Li Cunxu, who was then stalemated with Later Liang forces on the Yellow River, was fearful of diverting forces to save Zhou, but under the urging of Li Siyuan, Li Cunshen, and Yan Bao (), decided to do so. He ordered Li Siyuan and Yan to advance first toward You, and then sent Li Cunshen to reinforce them. Together, they defeated Khitan forces and lifted the siege on You. However, it was said that after this battle, You Prefecture became constantly under the threat of Khitan, which would send raiders to cut off food supply routes to You. Further, the Khitan emperor commissioned Lu as the military governor of his own Lulong Circuit (headquartered at Ping Prefecture), and Lu and his Han troops would serve as guides in every Khitan incursion into Jin territory. It was said that Lulong's prefectures became gravely stricken by the constant Khitan raids.