Is it proper

[Leanne]

one of my pet peeves is the use of a period not followed by a cap. i can accept no grammar, but feel if you use it. use it properly, or at least try to.

Oh, the irony

Like anything in writing, you really should know the rules before breaking them, so that any break actually has an impact rather than just being written off as ignorance by the reader. That is not to say that everyone who comes here should know all the rules of grammar or risk damage to dangling participles -- but if someone takes the time to point out a grammatical problem, it's usually because it's caused them to pause or feel awkward about a line and that's damn good advice in most cases. If you've done it deliberately, then it's feedback that tells you you've achieved your goal; if it's an accident, or ignorance, then you've learned something.

As a rule (not a hard and fast one) I really only use the uncapped i to imply that the personal is irrelevant or subdued in some way -- or if I use no punctuation or caps whatsoever in a poem, for a "clean" look.

As to enjambment, there's a thread here somewhere that Todd started on line breaks and it's a really good one, well worth a read. In poetry we have a limited space to say what we need to say, so not only does every word count, but also every dot or squiggle or space.