First, "lorry" is British English. So you'd never hear an American say it.
Second, the way I (an American) understand it, a lorry is a specific kind of vehicle specifically designed for commercial hauling or moving. In America, we call these by a lot of different names, like 18-wheeler, tractor trailer, big rig, and others. When we in America say truck, we are almost certainly referring to a pickup truck unless otherwise noted. So, if you say "truck" to an American, what they have in mind is probably not the same as when you say "lorry" to a Brit.