If the leaf skew to one side, there must be more sun shine on this side. So you should use one tinfoil to hide the skew side, then this side can not obtain sunshine, so it will grow to another. The leaf will be get back. You can get a piece of tinfoil from one cigarette case.
Redressing the Skew Leaf by tinfoil.
And you need pay attention to put a pot of clivia in the right direction under the sunshine, so you will avoid of skew leaves.
About how to put a pot of clivia under the sun shine, please view the following url:
http://www.clivia.net.cn/n593c39.aspx