I don't much agree with doing it this way, but if that's
what's happening then I will try to be nice and join in.

Right! but this is what teachers do in the classroom, so let me respond to these helpful comments.

Note this whole passage is a package leading one into a trance in which one
experiences the little folk.

or the "rustics."  F. R. Leavis says that Eliot "clearly thinks of them as yokels, clumsy, crude, gross"

Note that Tim's deep lane is a repetition.

And according to Helen Gardner, in the revisions of FQ, Eliot worked hard to avoid using the same or similar words close together. Here Eliot uses the repetition--perhaps to enforce the trance effect.

What is the symbolism of the dahlias?

An interesting question. But it's possible that Eliot would say, "because they were dahlias," which is what he told Hayward when he asked about something about the season mentioned in one of the Quartets, that it was that season.

Dahlias bloom all summer, if that's relevant. But Gardner said that he didn't decide on summer (as opposed to spring) until the last draft of East Coker--"summer midnight."

My dictionary says the flower was name for Andreas Dahl (1751–89)

Are there devices used in conjuring a trance which use electricity?

Yes, as I'm sure you know! I like the idea that the atmosphere is "charged," and no longer think that the etymology of "electric," from Greek amber, could be relevant.