From what I understand, the weapon involved in a cavalry's initial charge was a far less effective weapon than the horse itself. I can't imagine a lance killing more than one or (maybe) 2 people when initial impact was made, but imagine the kind of physical damage a mass of charging warhorses could do with just the sheer force of thier impact. This, I think, lends credence to Lafayette's idea of the lance as a psychological weapon. This is not to say that a lance would not be an incredibly deadly weapon. All the weight of a rider and his charging horse put into one small, sharpened point would, of course, be incredibly effective.
Yes, the strenght of the horse was also concentrating in the tip of the lance, so even protected by a full armor, you can get seriously injured if not dead. Take a read to this paragraph traslated from an spanish web site, about the battles of Janos Hunyadi and his unusual cavalry tactics:
¨The first Turkish warlord to receive Hunyadi's "calling card" of war was Beg Iszhak, commander of the Turkish garrison occupying Szendr. As punishment for past raids, Hunyadi caught up with Beg Iszhak's troops and forced them to make a stand. It was a regular battle with "irregular" tactics on Hunyadi's part. Iszhak assumed that, as usual, the Magyars would attack the main body of the Turks with cavalry. Hunyadi, however, had planned otherwise. Instead of sending his cavalry against the Turkish infantry, he sent his own elite foot soldiersto meet the central Turkish force in hand-to-hand combat. At the same time, the Hungarian cavalry attacked the enemy flanks which, unprepared for mounted assault, were soon dispersed. With this part of the job done, the cavalry turned its attention to the central Turkish troops, who were already flagging from fighting the Magyar infantry.
The battle was an unmitigated disaster for Beg Iszhak and put an end to his marauding on Hungarian soil.¨
Non nobis Domine...