Kabbalah zu Bereschit 19:24

Rabbi Yosi and Rabbi Chiya said: The Holy One, blessed be He, established the right way for us; happy are those who delve into the Torah. They approached him and kissed him. Rabbi Yosi applied to him the verse: "And all your children shall be taught of Hashem, and great shall be the peace of your children" (Isaiah 54:13). When they reached a field, they all sat down. That man asked what changed when the verse says, "And Hashem rained upon Sodom and upon Gomorrah" (Gen. 19:24), (i.e. why was the term Elohim not used)? And what changed during the Great Flood, when the term 'Elohim' is used, while the term Hashem (is not used at all)?