Like Kyrvias said. If you found a scroll, it must be the arcane version. After the summoning is completed, your mage must spend a few rounds or so forcing the elemental under his will. If this is successful, you can control the elemental as any other summoned monster. If it fails, the elemental will attack you, after which you can try to charm it with the rings of elemental control. You cannot use the ring until the elemental attacks you.
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