BBC English English Myself Lyrics

Quite an interesting question, this one. I'll start by giving words like 'myself', 'yourself', 'himself', a name - they are known as reflexive p___ouns. Now, you're asking this because you know that normally, reflexive p___ouns are used when the object of a sentence refers to the same person or thing as the subject - so, for example,

I am cooking for myself tonight.

Or,

She very quickly established herself as an important designer.

Another common use of the reflexive p___oun is for emphasis:

He planned the garden himself.

What you heard was different, and your guest was using 'myself' in a subject position. The answer to your question lies in a detail that you mention - that your visitor was from Ireland. Basically, what you heard was a specifically Irish use of the word. In Irish English the reflexive p___ouns 'myself', 'herself', 'himself' etc. can be used in a subject position. On the day when I was preparing this answer, I heard someone on the radio talking about a famous fashion designer and saying,

Himself and his wife have always been very nice to everyone.

In other varieties of English you can sometimes find the reflexive p___oun used in subject position when it appears together with another subject - so I found these examples:

Paul and myself went there.
Only myself and my family were affected by this.

You also point out that Lizzy didn't use this structure. The thing is that if two structures are possible, some people may have a personal preference for one or the other. But I think your question is really interesting because it shows how we need to be aware when we are listening to someone speaking that we may be hearing a very specific phenomenon!