In September 1756, Pennavaire entered the Seven Years War as a major general in Field Marshall James Keith's column, commanding five squadrons each of the Gens d'Armes and Prince of Prussia Cuirassiers. By early October 1756, at Lobositz, Pennavaire's cavalry brigade had been augmented with another squadron of the "Garde du Corps" (178 men), giving him a brigade of just under 2000. At 11:00, with the field still shrouded in mist, Pennavaire's troopers were sent to reconnoiter the Austrian line, supported by the Bayreuth Dragoons. Quickly, though, the reconnaissance turned into firefight as the right flank of cuirassiers was enfiladed by the fire of the Austrian occupying Sullowitz. Several squadrons of Austrian dragoons also charged, and Pennavaire's most forward troops were rescued by the Bayreuth dragoons. Subsequently, Frederick pulled the cavalry out of the battle, but they had served a purpose: Frederick knew where his opponent's strengths lay. The battle lasted another seven hours, but Pennavaire and his brigade were observers. In the course of the first moments of battle, the brigade overthrew two Austrian cavalry regiments, took three standards and captured Austrian Field Marshal Fürst Lobkowitz.