We've seen a recent example of such a lag: 2014-15. The tropical Pacific warmed up above the El Nino threshold by late 2014, but the Walker circulation did not show a consistent response until March 2015. This year is not identical (nature never is!) but has some similarities. You're right to point out that the planet-wide patterns of above-average temperatures is likely having an effect on MJO, ENSO, and other climate modes.