I don't like the overhead of

IEnumerable<OrderedDictionary>

You are repeating the column names for every row.
There is no check for count not matching in row versus header.

Consider

IEnumerable<IEnumerable<string>> 

Or

IEnumerable<string[]>

Somehow report if line does not match header

I don't like the overhead of

IEnumerable<OrderedDictionary>

You are repeating the column names for every row.
There is no check for count not matching in row versus header.

Consider

IEnumerable<IEnumerable<string>> 

Or

IEnumerable<string[]>

Somehow report if line does not match header

Split accepts char[]
Might as well support that