Before Humbert actually beds his nymphet, there is an extraordinary scene, at once rhapsodic, repulsive, and hilarious, in which Humbert excites himself to sexual climax while a (presumably) unaware Lolita wriggles in his lap. How is this scene representative of their ensuing relationship? What is the meaning of the sentence “Lolita had been safely solipsized” [p. 60], “solipsism” being the epistemological theory that the self is the sole arbiter of “reality”? Is all of Lolita the monologue of a pathological solipsist who is incapable of imagining any reality but his own or of granting other people any existence outside his own desires?
As understanding is colored by experience, and having been a child who was molested on the lap of a young man, I found nothing amusing or attractive in the scene.
Dolores - nicknamed Lo, Lola, Lolita by Humbert, has not been solipsized. She has become merely an extension of his needs. A few sentences before he says, "“I entered a plane of being where nothing mattered, save the infusion of joy brewed within my body. ” Certainly, Delores does not matter, and throughout the book Humbert compares her to other young girls he terms nymphets, and often considers how they might be exchanges one for another. He also considers what he will do with her and she grows “old” - as old as fifteen and is of no interest to him anymore.
Humbert only imagines himself and his actions. Lolita is his perfect “nymphet,” but only during her brief young age. There isn’t a single hint that he considers anyone but himself, and completely. Adults are the subject of his internal and brutal derision. His world only contains himself and his desires or pain. So, yes, all of the book is a monologue of a narcissist.
It appears that it is for the most part what you describe. The only diversion seems to have been when he brought her and her husband cash and a generous check. His intention was to buy her back and take her away, but she stood her ground. She asked him if she could still keep the money. It seems that when he left them with the check and money, and went on his way, that he had to have faced reality, even for a short glimpse.