As for 'izenkei',
1. A + "izenkei" form of a verb + ba, B...: A, so that B... / Since A, B...
ex.
にぎはひ豊かなれば、人には頼まるるぞかし。
2. A + "izenkei" form of a verb + do/domo, B...: even though A, B... / Although A, B...
ex.
二人行けど、行き過ぎ難き秋山をいかにか君が独り越ゆらむ。
中にとりこめ、雨のふるやうに射けれども、鎧よければうらかかず、あき間を射ねば手も負はず。
3. the particle "koso" can make a verb change to its 'izenkei' form. It emphasizes the
meaning of a sentence, creates some paradox, etc.
ex.
好きこそものの上手なれ。
若草の ね見むものとは 思はねど むすぼほれたる 心地こそすれ。
Hope this helps in some way.