C# :: Method Of Mapping Text File Dictionary To Class Fields

So I'm rewriting an old project of mine, and I'm trying to determine if there's truly any better way to map the data taken from a text file "dictionary" into the correct class fields for further processing. For example:

FNAME=MY_FIRST_NAME
ADDR=123 SOMEWHERE LN, NOWHERESVILLE, TX 01234
LNAME=MY_LAST_NAME
TOTCALLS=47

In each of these, I'd need the "value" (MY_FIRST_NAME, MY_LAST_NAME, etc) from the "keys" (FNAME, LNAME, etc) to be mapped to the proper class fields. Say, for example, I had this:

Class DataProcessing {
public string Address;
public string FirstName;
public string LastName;
public int TotalCalls;
...
}

I would need DataProcessing.Address to be set to the value in the ADDR key/value pair. The same would be true for each other field. The problem is that based on the text file's source (which isn't under my control, and won't be changed anytime soon), the key/value pairs are not always in the same place...so a second file could have the data as such:

TOTCALLS=47
ADDR=123 SOMEWHERE LN, NOWHERESVILLE, TX 01234
LNAME=DARKPOETCC'S LAST NAME
FNAME=DARKPOETCC'S FIRST NAME

Any smarter way to do this than looping through each line that was read in from the file, and determining where it belongs, such as (pseudo code follows):

IF FieldName == "TOTCALLS" THEN
//Assign to TotalCalls field
ELSEIF FieldName == "ADDR" THEN
//Assign to Address field
ELSEIF FieldName == (You get the picture...)
//Do thing N_Field