Elijah was God's friend. He loved God. But the rest of God's people didn't act like they loved God anymore. They didn't believe God's promises. They broke His alters. They tried to kill God's prophets [or friends]. Elijah believed he was the only prophet [or friend] that God had left and God's people were trying to kill him too. [A prophet is someone who was very brave about saying whatever God told him to say.]
"Go out and stand on the mountain in the presence of the LORD, for the LORD is about to pass by," God said to Elijah. So Elijah did.
[from the NIV] "A great and powerful wind tore the mountains apart and shattered the rocks before the LORD, but the LORD was not in the wind."
"After the wind there was an earthquake, but the LORD was not in the earthquake."
"After the earthquake came a fire, but the LORD was not in the fire."
"And after the fire came a gentle whisper. When Elijah heard it, he pulled his cloak over his face" [because people were afraid. They believed that if they looked at God they would die - God is a Holy God]
So Elijah went out and stood at the mouth of the cave (with the cloak over his face) and a voice said to him, "What are you doing here, Elijah?"
Elijah said, "Lord, I love you so much and I'm so upset! Look at what Your people have done! They've killed all your prophets [or friends]. I am the only one left!"
[NIV] The LORD said to him, "Go back the way you came, [I have work for you to do] I still have seven thousand friends in Israel—all whose knees have not bowed down to Baal and all whose mouths have not kissed him."
So Elijah went and did the things that God told him to do.
You can probably find a better version in a published Bible story book but that's what I mean about tinkering when you want to share some lesser heard Bible stories with children.