How did the clouds float according to the poem "I Wandered Lonely as a Cloud" by William Wordsworth?

According to the second line of Wordsworth's poem, the cloud

floats on high o'er vales and hills

The speaker, as we can see, is comparing himself to a cloud that is floating over the valleys and hills below, looking down on them. The cloud is "lonely" because it feels distant and alienated from the landscape it sees beneath it. The cloud listlessly views what it passes over but has no feeling of kinship with it. Today, we might imagine ourselves in an airplane looking down.
However, the detached emotion of being like a distant, floating cloud only lasts for the first two lines of the poem. It serves as a sharp contrast to what next occurs. The speaker moves from feeling lonely to suddenly being stopped and startled by the glorious sight of all the daffodils waving in the breeze before a lake. If the speaker was dulled down, emotionless, and lonely, he is now joyful and alive amid the dancing daffodils. It is as if he has arrived at a crowd of cheerful people.