"Does one ride cats?"
-lu' does not cause the object to work like a subject.
English has what are called "active" and "passive voice," in which the direct object of an active voice sentence becomes the subject of a passive voice sentence.
I throw the ball.
The ball is thrown by me.
Klingon doesn't have this. However, it is sometimes possible to translate Klingon sentences with -lu' into the English passive voice.
vIghro'mey lIgh ghotpu' People ride cats
vIghro'mey lulIghlu' Cats are ridden; someone unspecified rides cats
Notice that in Klingon, the object remains the object after attaching -lu'; the only thing that changes, aside from the removal of the subject (which is the point of -lu'), is the unusual prefix. The prefix you just have to memorize; the object still acts like an object.
It's just a matter of what syntax you choose for the English. It's not relevant to the Klingon syntax. Don't get confused between the two. The Klingon grammar is not affected by the English grammar.
Sometimes you can't easily translate Klingon -lu' into English passive voice. naDev ba'lu''a' Does one sit here? The verb has no object, so you can't say Is sat here?