1)
When did the coming episode occur?
1.
Rashi, citing 32 Midos of R. Eliezer Bno Shel R. Yosi ha'Gelili, Midah 1: It is written here 1 , for Elisha said, "Pi Shenayim of you Ru'ach will be to me" (2:9). We find that Eliyahu did eight wonders, and Elisha, 16. The 16 are written one after the other; this was written here due to the miracle of Meisha Melech Mo'av, via Elisha (verses 20-24). Splitting the Yarden counts like two miracles of Elisha (refer to 2:14:2:1).
2.
Malbim: This was when Elisha came to Shomron. When Eliyahu was taken, Elisha came, and there was war.
1
Really, this was when Meisha rebelled (1:1). (PF)