"I wandered lonely as a Cloud" is almost like a simpler version of "Tintern Abbey," one of Wordsworth’s other most famous works. In both poems, the memory of beautiful things serves as a comfort to the speaker even after the experience of viewing them has ended. He can always draw on his imagination to reproduce the joy of the event and to remember the spiritual wisdom that it provided. In the case of "I wandered lonely as a Cloud," we do not realize just how far in the future the speaker’s perspective is located until the fourth stanza, when he describes just how often the daffodils have comforted him.
The speaker’s joy ("bliss") upon remembering the daffodils is not as a powerful or long lasting as the original experience.
The speaker has no control over when the daffodils "flash" into his mind. The recollection is mysterious and spontaneous.