Idiomatic Scala for applying functions in a chain if Option(s) are defined

Is there a pre-existing / Scala-idiomatic / better way of accomplishing this?

def sum(x: Int, y: Int) = x + y

var x = 10
x = applyOrBypass(target=x, optValueToApply=Some(22), sum)
x = applyOrBypass(target=x, optValueToApply=None, sum)
println(x) // will be 32

My applyOrBypass could be defined like this:

def applyOrBypass[A, B](target: A, optValueToApply: Option[B], func: (A, B) => A) = {
  optValueToApply map { valueToApply =>
    func(target, valueToApply)
  } getOrElse {
    target
  }
}

Basically I want to apply operations depending on wether certain Option values are defined or not. If they are not, I should get the pre-existing value. Ideally I would like to chain these operations and not having to use a var.

My intuition tells me that folding or reducing would be involved, but I am not sure how it would work. Or maybe there is another approach with monadic-fors...

Any suggestions / hints appreciated!