Passing special characters in http get request

Have a webpage that is opened from another system with parameters that can contain extended ascii characters:

http://<host>/submitpage.cshtml?pname=SomeName

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The cshtml webpage reads the parameters as usual with:

var pname = Request["pname"];
and shows it on the page with @pname

Works fine for all browsers except IE (even IE11) when pname=Günther or another name with foreign characters; ü, ø and so on.

Example:

http://<host>/submitpage.cshtml?pname=Günther

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results in G�nther
The webpage is using <meta charset="UTF-8" />

Why does this work in Chrome and Opera but not in IE?
Any solution? I have no control over the submitting system, som the url cannot be encoded before submit.