What is the theme of Piano by D.H. Lawrence and what is the style in which he writes it?

"Piano," a poem by D.H. Lawrence, describes a man who is
listening to a woman singing and playing the piano.  This experience triggers the man's
memory and takes him "back down the vista of years" until he can see himself (in his
mind's eye) as a child listening to his mother playing the piano and
singing.

The singing woman might "burst into clamour," but
the "glamour" belongs to the man's "childish days," when he sat "in the cosy parlour"
and sang hymns to the accompaniment of "the tinkling
piano."

Although the man yearns for the past, he seems to
realize that it is irretrievable, as he says: "I weep like a child for the
past."

The poem consists of 3 stanzas, each of four lines. 
The rhyme scheme of each stanza is AA-BB.  The lines of the poem are fairly long, mostly
from 12-15 syllables each.

The poem is written in clear,
standard modern English.  There are several words that evoke the sound of the piano:
tingling, tinkling, boom.  There are also several words that tend to give the poem a
tinge of romanticism: vista, insidious, appassionato.